<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var obj = {
            id:1,
            name:'andy',
            msg:{
                age:18
            }
        };
        var o={};
        
        // for(var k in obj)
        // {
        //     o[k] = obj[k];
        // }
        // console.log(o);
        // o.msg.age = 20;
        // console.log(obj);

        console.log("---------------");
        Object.assign(o,obj);
        console.log(o);
        o.msg.age = 20;
        console.log(obj);
    </script>
</body>
</html>